Java 21 / React Developer (Spring Boot + TypeScript) — Circular Economy — Paris
Join a product team on a regulated circular-economy platform: Spring Boot microservices in Java 21, React/NX micro-frontends, PostgreSQL and GCP. A genuine 50/50 back and front role, 3 to 4 years of experience, Paris with 2 days a week on site.
- Spring Boot
- React / TypeScript
- GCP
Apply ↓ Up to EUR 500/day (freelance) — firm client budget
Abbeal is looking for a Java 21 + React/TypeScript developer to join a product team building the core platform of a circular-economy player, on a regulated extended producer responsibility scheme. A serious technical environment: 15 Spring Boot microservices, micro-frontend applications and GCP infrastructure.
The context
The platform handles contracting, declarations, eco-contributions and pricing scales for a recycling scheme. The business domain is rich and regulated: understanding the rule before writing the code is part of the job, not an afterthought.
On the technical side the project owns its standards: hexagonal architecture and DDD across several services, several hundred Flyway migrations in production, and one rule that is not up for discussion — no change without a test.
The role
- Build and evolve Spring Boot microservices in Java 21, with strict separation between domain, use cases, SPI ports and infrastructure adapters
- Contribute equally to React 18/19 TypeScript frontends in an NX monorepo with module federation — this is a genuine 50/50 back and front role
- Work the PostgreSQL data model, native SQL included, and version schemas with Flyway
- Write the tests that go with it: unit, feature and integration against a real database
- Turn regulated functional requirements into technical design, and push back when they do not hold
- Ship small, tested Merge Requests that stay within the agreed scope
What we are looking for
- 3 to 4 years of hands‑on development experience. That level is deliberate: this role is not open to very senior profiles
- Solid Java 21 in production. Kotlin is not required — it is a plus, not a prerequisite
- React 18/19 and TypeScript in production. Non‑negotiable: the frontend carries as much weight as the backend here
- Spring Boot 3.4 / Spring 6: Web, Data JPA, Security, Cloud
- JPA / Hibernate 6 and PostgreSQL, with real SQL fluency
- NX monorepo and module federation, TanStack React Query, React Final Form, react‑intl
- Testing: JUnit 5 and AssertJ on the backend, Jest and Testing Library on the frontend. Non‑negotiable on this project
- Git, GitLab CI, Agile with JIRA
- Fluent French is required: part of the code, tests and documentation are written in French, and ceremonies are held in French
- Based in the Paris region and available for 2 days a week on the client site
- Available from 28 September 2026
Nice to have
- Kotlin — the project's historical language, but no longer a condition for the role
- DDD and hexagonal architecture
- Docker multi‑stage builds and GCP: App Engine, Cloud Run, Cloud Storage, Pub/Sub
- Asynchronous messaging such as RabbitMQ or Kafka, transferable to Pub/Sub
- Cucumber / BDD, with Gherkin scenarios written in French
- Third‑party API integration: e‑signature, public registries, CRM, banking flows
- Feature flags (Unleash), SonarQube, JaCoCo, Cypress
- Terraform / Ansible, application security with JWT and fine‑grained profile permissions
Conditions
- Freelance, up to EUR 500/day — the client budget is firm at that cap
- Paris, hybrid: 2 days a week at the client's offices near Gare de Lyon, the rest with the team
- 1 to 2 remote days a week once up to speed and autonomous